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Method for strengthening anaerobic digestion of excess sludge by coupling alkaline pulping waste liquid with sludge alkaline thermal conditioning

A technology of pulping waste liquid and anaerobic digestion, which is applied in the field of solid waste recycling, can solve the problem of high cost of chemicals, and achieve the effect of significant application value, shortening fermentation period and increasing yield.

Inactive Publication Date: 2020-06-09
GUANGXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the existing sludge chemical conditioning technology uses exogenous chemicals such as sodium hydroxide. Although the effect of alkali conditioning is better than thermal conditioning, it is completely dependent on exogenous chemicals, resulting in high cost of chemicals.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Take the pulping waste liquid by caustic soda method, adjust the solid content to 5% of the remaining sludge from pulping and paper mills, add the waste liquid from pulping by caustic soda method to adjust the pH value of the sludge to 11, and then raise the temperature to 70°C and keep it warm for 12 hours To obtain the alkali-heat conditioned sludge, after the above sludge is cooled to 35°C, the alkali-heat conditioned sludge and the medium-temperature anaerobic inoculation sludge are mixed evenly at a ratio of volatile solids of 0.5, and put into the anaerobic digestion reaction The temperature of the water bath was set at 35°C, and the final anaerobic digestion obtained a cumulative methane production of 2695ml. Compared with the control group of untreated sludge, the final cumulative methane production increased by 250%, and the fermentation period required to stabilize the cumulative methane production was shortened. to 18 days.

Embodiment 2

[0034] Take alkaline hydrogen peroxide chemical mechanical method (APMP) pulping waste liquid, adjust the solid content to 5% of the residual sludge taken from the pulp and paper mill, add caustic soda pulping waste liquid to adjust the pH value of the sludge to 9 , after raising the temperature to 110°C for 1 hour to obtain alkali-heat conditioned sludge, after cooling the above sludge to 55°C, mix the alkali-heat conditioned sludge and high-temperature anaerobic inoculated sludge with a volatile solid ratio of 0.5, and mix them evenly , put it into the anaerobic digestion reactor, set the temperature of the water bath at 55°C, and finally obtain a cumulative methane production of 1617ml. Compared with the control group of untreated sludge, the final cumulative methane production increased by 110%, and the cumulative methane production reached The fermentation cycle required for stabilization is shortened to 15 days.

Embodiment 3

[0036] Take the oxygen delignification filtrate from the cooking and bleaching section, adjust the solid content of the remaining sludge from the pulp and paper mill to 5%, add caustic soda pulping waste liquid to adjust the pH value of the sludge to 12, and then raise the temperature to 90 After 4 hours of heat preservation at ℃, the alkali-heat conditioned sludge was obtained. After the above sludge was cooled to 35 ℃, the alkali-heat conditioned sludge and the medium-temperature anaerobic inoculated sludge were mixed evenly at a ratio of volatile solids of 0.5. into the anaerobic digestion reactor, the temperature of the water bath was set at 35°C, and finally the cumulative methane production was 1078ml. Compared with the control group of untreated sludge, the final cumulative methane production increased by 40%. Cycle shortened to 20 days.

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Abstract

The invention discloses a method for strengthening anaerobic digestion of excess sludge by coupling alkaline pulping waste liquid with sludge alkaline heat conditioning, which belongs to the field ofsolid waste recycling, and comprises the following steps of: adding alkaline pulping waste liquid into sludge to regulate the alkaline pulping waste liquid to be alkaline by utilizing the residual alkali characteristic of the alkaline pulping waste liquid to obtain alkalized sludge; sending the alkalized sludge into an alkaline thermal reaction device to strengthen sludge hydrolysis and cell disruption; sending the alkaline heat quenched and tempered sludge into an anaerobic digestion device, and converting the sludge into biogas under the action of anaerobic microorganisms. The alkaline pulping waste liquid generated in the pulping and papermaking process is used as an alkali source for sludge alkali heat tempering; according to the method, coupling cooperative treatment and recycling oforganic waste in the pulping and papermaking process are achieved, the economical efficiency of sludge alkali-heat conditioning is improved, the methane yield can be increased, the fermentation periodis shortened, powerful support is provided for recycling treatment of residual sludge in the pulping and papermaking industry, and the method has remarkable application value.

Description

technical field [0001] The invention relates to the field of solid waste recycling, in particular to a method for enhancing anaerobic digestion of excess sludge by coupling alkaline pulping waste liquid with sludge alkali-heat conditioning. Background technique [0002] The pulp and paper industry is an important industry for the development of the national economy, and it is also a key source of industrial wastewater pollution. In the process of pulping and papermaking wastewater treatment, organic pollutants can be converted into excess sludge (hereinafter referred to as "sludge") through biochemical pathways. Sludge is produced in a large amount, has complex components, and is difficult to deal with. [0003] Sludge conditioning-anaerobic digestion is an effective sludge treatment method. Heat and / or alkali treatment can promote sludge dissolution, cell disintegration, and shorten the anaerobic digestion cycle. Existing research has lowered the temperature of thermal co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/04C02F11/10C02F11/00C02F103/28
CPCC02F11/00C02F11/04C02F11/10C02F2103/28
Inventor 张健王双飞吴宛励王志伟沙九龙朱红祥
Owner GUANGXI UNIV